Quel est l'impact de l'annonce d'un changement du PDG d'une entreprise cotée en bourse aux Etats-Unis sur le prix de ses actions ?

Abstract

The purpose of this thesis was to determine whether the announcement of a CEO change by a listed company in the United States has an impact on its share price. To do this, we proceeded as follows: we first presented the literature review about CEO changes. Then, we presented the concepts of the "Market model" and the "Efficient market hypothesis". After that, we presented the methodology necessary to conduct this event study. We analyzed a sample of 121 companies belonging to the S&P 500 index. After that, we analyzed sub-samples according to the age of the new CEOs recruited and whether they were recruited internally or externally. The statistically significant cumulative average abnormal returns (CAARs) obtained for the entire sample are (slightly) negative, the statistically significant CAARs obtained for the sub-sample of CEOs recruited internally are negative also, the statistically significant CAARs obtained for the sub-sample of CEOs recruited externally are positive. Finally, the statistically significant CAARs obtained for the sub-sample of new young CEOs recruited are positive and the statistically significant CAARs obtained for the sub-sample of new older CEOs recruited are negative.